Grids for vapor-liquid contact apparatus

ABSTRACT

949,529. Gas-liquid contact columns. FRITZ W. GLITSCH &amp; SONS Inc. Feb. 21, 1962 [March 3, 1961], No. 6809/62. Heading B1R. A grid element for vapour-liquid contact apparatus comprises a structural member including a horizontal portion, formed with a plurality of spaced openings therein constituting upright passages, characterized in that the member is provided with a plurality of spaced reinforcing ribs extending from the horizontal portion, and the openings in the horizontal portion extend into the ribs and thus form horizontal passages therethrough of smaller area than the upright passages. The ribs alternately extend in opposite directions from the horizontal portion. Preferably the horizontal passages are more than one-tenth and less than one-half of the combined area of the upright passages. Fig. 5 shows a grid section 14 formed initially from a flat sheet having a multiplicity of relatively large openings 15 of any desired configuration formed in closely spaced relationship. The section is bent longitudinally upon itself to form a plurality of upright, reinforcing, parallel ribs 16 and 17 which are connected by horizontal elements or webs 18. The openings are of such size that opposed portions or segments 19 and 20 extend into the legs 16 and 17 forming horizontal passages. Each grid section may be constructed of a plurality of elongate narrow members 21, or may be a one-piece construction. The angles between adjacent layers may be 30 degrees, 45 degrees, 60 degrees, or 90 degrees.

Feb. 26, 1963 F. w. w|-- 3,079, 34

GRIDS FOR VAPOR-LIQUID CONTACT APPARATUS Filed March 3, 1961 INVENTOR Franc/s W, W/nn ATTORNEYS 3,079,134 GS FER VAPUR-LI'QUID CONTAT AFPARATUS Francis W. Winn, Dailas, Ten, assignor to Fritz W.

Glitsch 8; Sons, Inc, Dallas, Tex a corporation of Delaware Fiied Mar. 3, 1961, Ser. No. 93,221 8 (Iiaims. (Qt. 2611l3) This invention relates to new and useful improvements in grids for vapor-liquid contact apparatus.

In the vapor-liquid contact art, it is most desirable to employ apparatus that improves the quality and quantity of a product without increasing reflux rates or the uneconomical use of introduced utilities, such as steam. Also, it is important to obtain close fractionation and separation of the feed stock constituents for purity and the elimination of harmful or undesirable residual elements, such as con-carbon and metals which are present in many chemical and petroleum feed stocks.

It is one object of the invention to provide an improved grid for vapor-liquid contact apparatus which insures intimate contact between vapors and liquids so as to obtain high efficiency, low pressure drop, and reduced temperatures.

Another object of the invention is to provide an improved vapor-liquid contact grid for use in vacuum and other services, such as the separation of light and heavy gas oils from crude oil or crude oil residuum under vacuum for subsequent use as a feed stock in a catalytic cracking process, whereby the pressure drop is minimized and the product is of improved quality.

Another object of the invention is to provide an improved vapor-liquid contact grid which is of economical manufacture, which is designed structurally so as to be self-supporting over relatively long spans, and which may be formed of light gauge or sheet metal of any desired analysis ranging from carbon steel to stainless steel, nickel or copper base alloys.

A particular object of the invention is to provide an improved grid, of the character described, which is adapted to be formed in elongate, relatively narrow, rectangular sections to permit the passage thereof through the manholes of pressure vessels and the assembly of the sections in superimposed layers with each layer resting on the layer therebelow and oriented at any desired angle thereto, such as 30, 45, 60, or 90.

A important object of the invention is to provide an improved grid, of the character described, wherein each layer has a large, upright, vapor passage area which is in excess of 59% of the horizontal area of the layer and an intercommunicating, horizontal, vapor passage area between its upper and lower margins which is not less than of the upright vapor passage area of said layer.

A further object of the invention is to provide an improved grid, of the character described, wherein the layers are constructed so as to have structural rigidity for withstanding upward and downward loads or forces and so as to space the horizontal portions of said layers a distance apart sufiicient to insure commingling of the ascending vapors substantially throughout the entire volume or space occupied by each layer in the horizontal plane by means of openings or passages extending vertically, chordally and radially in every direction.

An object of the invention is to provide an improved grid, of the character described, having adequate vapor passages in the horizontal planes of the layers to insure the flow of vapor and distribution thereof within said layers and prevent maldistribution or channeling of the vapor through certain portions of said layers.

3,h79,l3 i Fatented Feb. as, less Another object of the invention is to provide an im proved grid, of the character described, having sufiicient surficial area for vapor-liquid contact without unduly restricting the flow of the ascending vapor or its countercurrent contact with the descending liquid.

A further object of the invention is to provide an improved grid, of the character described, having suflicient mass and surficial area in both the horizontal and vertical planes so that fractions of the heavy constituents are conducted downwardly in condensed form and the vapor is permitted to rise.

An object of the invention is to provide an improved grid, of the character described, wherein the undesirable heavy constituents of the feed stock as well as the con-carbon and metal content thereof are removed by the action of the descending liquid whereby said grid is self-cleaning.

Another object of the invention is to provide an improved grid, of the character described, wherein the upright vapor passages and the intercommunicating horizontal vapor passages of the grid layers are formed by a plurality of openings of desired configuration which are so arranged that the structural strength and rigidity of said layers are not impaired to an extent that would result in stresses in excess of the allowable limit of the material employed at operating temperatures and loads.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawing, wherein examples of the invention are shown, and wherein:

FIG. 1 is a transverse, vertical, sectional view of a portion of a vapor-liquid contact vessel and a grid constructed in accordance with the invention,

FIG. 2 is an enlarged, plan view of a portion of one of the layers of the grid,

FIG. 3 is a transverse, vertical, sectional View, taken on the line 33 of FIG. 2,

FIG. 4 is a transverse, vertical, sectional view, taken on the line 44 of FIG. 2,

FIG. 5 is a perspective view of a portion of one of the grid layers, and

FIG. 6 is a view, similar to FIG. 3, showing a modification of the invention.

In the drawing, the numeral it) designates the cylindrical wall or shell of a vapor-liquid contact vessel having an annular ring 11 secured to and extending radially inward therefrom. A grid 12, embodying the principles of the invention, is adapted to be supported by the ring 11 so as to extend transversely of the interior of the vessel 16 and includes a plurality of superimposed layers or tiers 13. In order to facilitate installation and assembly of the grid, each layer or tier 13 is formed in elongate, relatively narrow, substantially rectangular sections 14 of sufficient length to span the distance between opposed portions of the supporting ring (FIG. 1) or intermediate supports (not shown). The relatively narrow width of the sections 14 permits the passage of the same through manholes (not shown) which usually provide the only access to the interior of the vapor-liquid contact vessel. As will be explained, each section is structurally designed so as to be self-supporting over relatively long spans and is formed of light gauge or sheet metal of any desired analysis ranging from carbon steel to stainless steel, nickel or copper base alloy.

Each grid section 14 has a multiplicity of relatively large openings 15 of any desired configuration, such as the illustrated circular shape, formed therein in closelyspaced relationship (FIG. 5). After formation of the 3 openings 15, the section is bent longitudinally upon itself to provide a plurality of upright, longitudinal, reinforcing flanges, legs or ribs 16 and 17 of relatively narrow width which are substantially parallel and whichare connected by substantially horizontal elements or webs 18. It is noted that the openings are. of-such relative size that opposed portions or segments 19 and 20 thereof extend into the legs 16 and 17 and that the webs 18 are of very narrow width (FIGS. 3-5). As a result, the opening portions 19 and 20. are disposed. in upright planes and form horizontal passages through the grid section as shown most clearly inFIG. 4. The remainder. of. the. opening extends. horizontally and provides an upright passage through the grid section. Adjacent ones of the legs extend in opposite directions, preferably, at'righ't angles to the webs 18, whereby the section has alternate upstanding and depending legs.

For economy of manufacture, each. grid section 14 may be constructed. of a plurality of elongate, narrow members or strips 21 with each strip having a single row of the openings 15. and the upstanding and depending, coextensive legs 16 and 17 on its longitudinal margins. The strips 20 are substantially Z-shaped in cross-section and have their adjacent upstanding. and depending legs welded or otherwise securedtogether. in abutting, parallel relationship (FIGS. 1-3and 5.). If desired,. how ever, e'ach grid section may be of one-piece construction' as shown bythe numeral 22' in FIG. .6. After the formation of openings 23, similar to theopenings .15, the one-piece grid section 22 isbent upon itself to provide upstanding and depending, longitudinal flanges, legs or ribs 24 and 25 which are similar to the legs 16. and 17 and in which opposed portions 26 and 27 of the openings are disposed. Due to this integral construction, the adjacent or intermediateupstanding and depending legs are joinedas shown at 28 and 29 and need not be welded or otherwise secured together. It is pointed out that the one-piece and multi-piececonstructions may be combined in that,. two. or more wide strips may be utilized to. form eachsection. The .widestrips may have two or more rows of openings and two or more integral legs with theirmarginal legs being welded or otherwise secured to the marginal legs of adjacent strips. The open.-. ings of each grid section. are alined intransverse rows for greater strength with less material; however, it is readily apparent that said openings may bestaggered or oifset with respect to adjacent openings.

The gridsections 14 are installed in. the layers or tiers 13 illustrated in FIG. 1. The depending legs 17 of the lowermost layer rest on the ring 11 and the overlying layer has it's depending legsv restingupon the upstanding legs 16 of .said lowermost layer. This assembly of. the grid sections is. continued until the desired thickness of grid is obtained. The legs of adjacent layersextend in angular relation to .one another, such. as 30, 45, 60 or. 90, the latter angular relationship being shown for simplicity of illustration. Due to this angular relationship, the openings and webs .18 of adjacent layers .of the grid are spaced from one another and their legs 16 and 17.are prevented from nesting and from engaging the webs of one another so as to interfere'withv the horizontal passages formed by the portions 19 and of said openings. 7

In use, the upright and horizontal passages of the grid sections 14 intercommunicate to permit the flow of ascendingvapor and descendingliquid through the grid 12. Due to the upstanding and depending longitudinal legs Hand .17, unobstructed, longitudinal passages are provided in the upper and lower surfaces of the grid sections and these passages are in direct communication with the openings. 15 and their upright. portions 19 and 20 as well as with the longitudinal passages 'of' the'grid.

layers 13 thereabove' and therebelow: Accordingly, the

longitudinal passages ifo'rm parts of both thehorizontal'" and upright passages; In order to minimize interference 4%- with the flow of the liquid and vapor and insure thorough commingling thereof, the combined area of the upright passages of each grid layer is in excess of 50% of the horizontal area of the layer and the combined area of the horizontal passages of said layer is not less than 10% of the area of said upright passages.

It is pointed out, however, that the upstanding and depending legs of each grid section provide structural rigidity sufiicient to withstand upward and downward loads or forcesas well as supportthe weight of the section whereby said section is self-supporting over rela tively long spans and does not flex or bend unduly under operating conditions. Also, the legs, together with the Webs 18, provide sufiicient surficial area for vapor-liquid contact without unduly restricting the flow of the ascending vapor or its counter-current contact with the descending liquid and for conducting the heavy constituents downwardly in condensed form as well as permitting the release and upward movement of vapor which is confined in bubbles or globules. Particular attention is directed-to the fact that the construction of the grid insures even distribution and intimate and close contact of the vaporand-liquid and prevents dead or inactive areasor spots as Well as channelingof the vapor and/ or liquid. in isolated portions of said grid or-its layers. It isiur thernoted that the passages extend in all directions including vertical, horizontal and chordal.

The grid is adapted for use'in vacuum and other services, such as the separation of light and heavy gas oils from crude oil under vacuum for subsequent use as a feed stock. in a catalytic cracking process. The descending liquid contacts the entire area of the grid so as to wash off and cleanse its layers of undesirable con-carbon;

tramp metals and heavy or high boiling point constituents of the chemical or crude oil feed stock. These undesirable constituents are collected and withdrawn from the vessel for subsequent processing or all, or a portionthereof, may be revaporized by heating and returned to said vessel. It iscontemplated'that more than one grid may be employed in a single vessel; for example, a second .grid may bemounted in the condensing zone or circulating reflux section in place of conventional fractionating trays.

The foregoing description of the invention is explanatory thereof andvarious changes in the size, shape and materials, aswell as in the'details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A grid for vapor-liquid contact apparatus including a plurality of superimposed layers, each layer including a substantially horizontal portion and a plurality of spaced. reinforcing ribs upstanding and depending from the substantially horizontal portion, the depending ribs of each layer resting on the upstanding ribs of the underlying layer whereby the substantially horizontal portions ofadjacent layers are spaced apart, said substantially horizontal portions having a plurality of closely spaced openings of relatively large size to provide upright pas sages through the'layers, the openings being formed'be tween the ribs with small areas thereof extending into the inner portions of said ribs to provide substantially horizontal passages intermediate the upper and lower margins of each layer of less area than the upright passages, said ribs having continuous outer portions to reinforce said layers.

2. A grid as set forth in claim 1 wherein the min forcing ribs of each layer alternately upstand and depend and extend in angular relation to the ribs of adjacent layers whereby the substantially horizontal passages of adjacent layersare disposed in angular relationship.

3. A grid as set forth in claim 1 wherein the upright passages of each layerhave a combined area in excess of one-half of the horizontal area of thelayer, the combined area of the substantially horizontal passages of each layer being not less than one-tenth of the combined area of said upright passages whereby the grid has sufiicient surficial area for vapor-liquid contact without unduly restricting vertical flow therethrough.

4. A grid as set forth in claim 1 wherein each layer includes a plurality of elongate relatively narrow rectangular sections disposed in side by side relationship, the reinforcing ribs extending longitudinally of and being substantially coextensive with the sections.

5. A grid as set forth in claim 4 wherein the sections of the layers are of integral one piece construction, the reinforcing ribs being of relatively narrow width and including pairs of flanges integral with said sections and in face to face relationship.

6. A grid as set forth in claim 4 wherein each section of the layers includes at least a pair of elongate strips, each strip having a web portion and upstanding and depending flanges at its longitudinal margins, the flanges of adjacent strips being secured together to form the reinforcing ribs.

7. A grid as set forth in claim 1 wherein each layer includes a plurality of elongate strips, each strip having a web portion and upstanding and depending flanges at its longitudinal margins, the flanges of adjacent strips being secured together to form the reinforcing ribs.

8. A grid as set forth in claim 1 wherein the reinforcing ribs of each layer are substantially parallel, the openings of the substantially horizontal portions of said layers being of substantially uniform size and arrangement whereby the upright and horizontal passages have substantially uniform areas and spacing.

References Cited in the file of this patent UNITED STATES PATENTS 2,515,090 Linder July 11, 1950 2,767,966 Chave Oct. 23, 1956 2,918,265 Williams et a1 Dec. 22, 1959 2,998,234 Haselden Aug. 29, 1961 

1. A GRID FOR VAPOR-LIQUID CONTACT APPARATUS INCLUDING A PLURALITY OF SUPERIMPOSED LAYERS, EACH LAYER INCLUDING A SUBSTANTIALLY HORIZONTAL PORTION AND A PLURALITY OF SPACED REINFORCING RIBS UPSTANDING AND DEPENDING FROM THE SUBSTANTIALLY HORIZONTAL PORTION, THE DEPENDING RIBS OF EACH LAYER RESTING ON THE UPSTANDING RIBS OF THE UNDERLYING LAYER WHEREBY THE SUBSTANTIALLY HORIZONTAL PORTIONS OF ADJACENT LAYERS ARE SPACED APART, SAID SUBSTANTIALLY HORIZONTAL PORTIONS HAVING A PLURALITY OF CLOSELY SPACED OPENINGS OF RELATIVELY LARGE SIZE TO PROVIDE UPRIGH PASSAGES THROUGH THE LAYERS, THE OPENINGS BEING FORMED BETWEEN THE RIBS WITH SMALL AREAS THEREOF EXTENDING INTO THE INNER PORTIONS OF SAID RIBS TO PROVIDE SUBSTANTIALLY HORIZONTAL PASSAGES INTERMEDIATE THE UPPER AND LOWER MARGINS OF EACH LAYER OF LESS AREA THAN THE UPRIGHT PASSAGES, SAID RIBS HAVING CONTINUOUS OUTER PORTIONS TO REINFORCE SAID LAYERS. 